New findings refute groupthink, proving that wisdom of crowds can prevail

June 12, 2017
Credit: CC0 Public Domain

Anyone following forecasting polls leading up to the 2016 election likely believed Hillary Clinton would become the 45th president of the United States. Although this opinion was the consensus among most political-opinion leaders and media, something clearly went wrong with these prediction tools.

Though it may never be known for certain the reasons for the discrepancy between public perception and the electoral reality, new findings from the University of Pennsylvania's Damon Centola may offer a clue: the wisdom of a is in the .

The classic "wisdom of crowds" theory goes like this: If we ask a of people to guess an outcome, the group's guess will be better than any individual expert. Thus, when a group tries to make a decision, in this case, predicting the outcome of an election, the group does a better job than experts. For market predictions, geopolitical forecasting and crowdsourcing product ideas, the wisdom of crowds has been shown to even outperform industry experts.

That is true—as long as people don't talk to each other. When people start sharing their opinions, their conversations can lead to social influences that produce "groupthink" and destroy the wisdom of the crowd. So says the classic theory.

But Centola, an associate professor in Penn's Annenberg School for Communication and School of Engineering and Applied Science and director of the Network Dynamics Group, discovered the opposite. When people talk to each other, the crowd can get smarter. Centola, along with Ph.D. candidate Joshua Becker and recent Ph.D. graduate Devon Brackbill, published the findings in Proceedings of the National Academy of Sciences.

"The classic theory says that if you let people talk to each other groups go astray. But," said Centola, "we find that even if people are not particularly accurate, when they talk to each other, they help to make each other smarter. Whether things get better or worse depends on the networks.

"In egalitarian networks," he said, "where everyone has equal influence, we find a strong social-learning effect, which improves the quality of everyone's judgements. When people exchange ideas, everyone gets smarter. But this can all go haywire if there are leaders in the group."

An influential opinion leader can hijack the process, leading the entire group astray. While opinion leaders may be knowledgeable on some topics, Centola found that, when the conversation moved away from their expertise, they still remained just as influential. As a result, they ruined the group's judgment.

"On average," he said, "opinion leaders were more likely to lead the group astray than to improve it."

The online study included more than 1,300 participants, who were placed into one of three experimental conditions. Some were placed into one of the "egalitarian" networks, where everyone had an equal number of contacts and everyone had equal influence. Others were placed into one of the "centralized" networks, in which a single opinion leader was connected to everyone, giving that person much more influence in the group. Each of the networks contained 40 participants. Finally, Centola had several hundred subjects participate in a "control" group, without any social networks.

In the study, all of the participants were given a series of estimation challenges, such as guessing the number of calories in a plate of food. They were given three tries to get the right answer. Everyone first gave a gut response.

Then, participants who were in social networks could see the guesses made by their social contacts and could use that information to revise an answer. They could then see their contacts' revisions and revise their answers again. But this time it was their final answer. Participants were awarded as much as $10 based on the accuracy of their final guess. In the control group, participants did the same thing, but they were not given any social information between each revision.

"Everyone's goal was to make a good guess. They weren't paid for showing up," Centola said, "only for being accurate."

Patterns began to emerge. The control groups initially showed the classic wisdom of the crowd but did not improve as people revised their answers. Indeed, if anything, they got slightly worse. By contrast, the egalitarian networks also showed the classic wisdom of the crowd but then saw a dramatic increase in accuracy. Across the board, in network after network, the final answers in these groups were consistently far more accurate than the initial "wisdom of the crowd."

"In a situation where everyone is equally influential," Centola said, "people can help to correct each other's mistakes. This makes each person a little more accurate than they were initially. Overall, this creates a striking improvement in the intelligence of the group. The result is even better than the traditional wisdom of the crowd! But, as soon as you have opinion leaders, social influence becomes really dangerous."

In the centralized networks, Centola found that, when the opinion leaders were very accurate, they could improve the performance of the group. But even the most accurate opinion leaders were consistently wrong some of the time.

"Thus," Centola said, "while opinion leaders can sometimes improve things, they were statistically more likely to make the group worse off than to help it.

"The egalitarian network was reliable because the people who were more accurate tended to make smaller revisions, while people who were less accurate revised their answers more. The result is that the entire crowd moved toward the more accurate people, while, at the same time, the more accurate people also made small adjustments that improved their score."

These findings on the wisdom of crowds have startling real-world implications in areas such as climate-change science, financial forecasting, medical decision-making and organizational design.

For example, while engineers have been trying to design ways to keep people from talking to each other when making important decisions in an attempt to avoid groupthink, Centola's findings suggest that what matters most is the network. A group of equally influential scientists talking to one another will likely lead to smarter judgments than might arise from keeping them independent.

He is currently working on implementing these findings to improve physicians' decision-making. By designing a social network technology for use in hospital settings, it may be possible to reduce implicit bias in physicians' clinical judgments and to improve the quality of care that they can offer.

Whether new technologies are needed to improve the way the groups talk to each other, or whether we just need to be cautious about the danger of opinion leaders, Centola said it's time to rethink the idea of the of crowds.

"It's much better to have people talk to each other and argue for their points of view than to have opinion leaders rule the crowd," he said. "By designing informational systems where everyone's voices can be heard, we can improve the judgment of the entire group. It's as important for science as it is for democracy."

Explore further: A simple reward system could make crowds a whole lot wiser

More information: Joshua Becker el al., "Network dynamics of social influence in the wisdom of crowds," PNAS (2017). www.pnas.org/cgi/doi/10.1073/pnas.1615978114

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ddaye
not rated yet Jun 12, 2017
I'd like to see a credible estimate for the total expenditures on all forms of sponsored US opinion leading. I don't see the point of pondering democratic speech systems --there's no way or venue to escape opinion leading and skewing.
Dingbone
Jun 13, 2017
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antialias_physorg
not rated yet Jun 13, 2017
Although this opinion was the consensus among most political-opinion leaders and media, something clearly went wrong with these prediction tools.

...or the election could have been rigged (which would be one possible explanation of the disparity). But I guess the FBI is looking into that one.

The classic "wisdom of crowds" theory goes like this: If we ask a group of people to guess an outcome, the group's guess will be better than any individual expert.

Try having a crowd play chess against a grandmaster. See how that turns out. (We tried that in a course for project manager with connect-4. Bizzarely I had read a thesis on that game just a few days before the experiment. Result: If you have an expert, don't let the crowd do diddly squat)

If you have to make a group devision on something that seems like a matter of opinion: Don't.
Find a metric. Work out the problem. That way you nullify the negative effect of 'opinion leaders'.
Dingbone
Jun 13, 2017
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Dingbone
Jun 13, 2017
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TheGhostofOtto1923
5 / 5 (1) Jun 13, 2017
And then you have crowds like this
https://youtu.be/5WQS7_2J37Y

-I am sure there is a constructive opinion in there somewhere. It probably retards the synthesis of new ideas when you put yours on signs and banners.

And when do crowds become tribes and the tribal dynamic (us vs them) supplants reason? This can happen in crowds of people without masks as well, like those in the article.

These vids are fascinating. I watched them for hours yesterday.

Is it 2 crowds or one big crowd with differing perspectives? And what about the crowd in the middle - the police. Then there's the crowd at the periphery - the media - who may even be causing the whole dialectic or at least creating the atmosphere and setting the rules of engagement.
antialias_physorg
not rated yet Jun 13, 2017
If you have no experts at hand and the matter is inherently fuzzy then using 'crowd wisdom' is fine. But if I have an ecotrophologist on hand for a estimating the number of calories on a platter I'd take his/her word over the crowd opinion any day.
Although this opinion was the consensus among most political-opinion leaders and media, something clearly went wrong with these prediction tools.

This isn't a good example. The results published in the media are based on polls - i.e. crowd sourcing.
So this is actually a counterexample to crowd sourcing.

Polling mechanisms don't account for factors like:
- people being unwilling to out themselves as having made a seemingly immoral/unpopular choice. Even in a seemingly anonymous format.
- people who do make such extrem(ist) choices being more motivated to go vote than those who think they're part of the majority.

Crowd sourcing can carry inherent bias - even if the polling is set up in an unbiased way.
Dingbone
Jun 13, 2017
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TheGhostofOtto1923
not rated yet Jun 13, 2017
This is not opinion of crowd but this one of some individual... The wisdom of crowds can be never infered from opinion of single individual by its very definition
So you're saying that one individual gave both sides their diametrically opposed opinions. I say it's not one individual but one issue - entirely artificial, completely fabricated - which gives each side their opinions.

But the real issue and the one they're not arguing is the survival of the 2 party system, which is why the artificial one can NEVER have a resolution. Democracy is based on the tribal dynamic... internal amity combined with external enmity.

Xmas soccer games between Germans and brits was considered treason.
antialias_physorg
5 / 5 (1) Jun 13, 2017
The reason why we pay experts is not getting more correct solution, but faster one.

Soooo..you'd be OK with crowd sourcing a medical diagnosis? I know I wouldn't.
Eikka
not rated yet Jun 15, 2017
The usage of experts therefore isn't recipe for getting less fuzzy decission, only faster decission because experts already invested their time and your money into its preparation.


Actually, if you have multiple experts and can rank them in some order of importance, you can apply the wisdom of crowds effect and arrive at more precise predictions or estimates.

I remember a case, though I forget the name of the ship, that had sunken and found by consulting experts to estimate where it would have drifted underwater before it hit the bottom. Each individual estimate was up to tens of miles off, but the aggregate was within hundreds of yards from where the ship was actually found.

Soooo..you'd be OK with crowd sourcing a medical diagnosis? I know I wouldn't.


From the general public, perhaps not, but from a crowd of medical professionals, nurses, doctors assistants... - why not?

Though on the other hand, many folk remedies work, do they not?
matica
5 / 5 (1) Jun 16, 2017
"Anyone following forecasting polls leading up to the 2016 election likely believed Hillary Clinton would become the 45th president of the United States. Although this opinion was the consensus among most political-opinion leaders and media, something clearly went wrong with these prediction tools."

What went wrong was that the dishonest media and the leading pollsters were deliberately constructing misleading polls to discourage Trump supporters by falsely implying that Trump had no chance of winning.
COCO
not rated yet Jun 19, 2017
Globalists got their behinds kicked this time - they will learn from this or not, as the Deep State continues to prevail.

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